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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        fn();
        function fn() {
            let arr = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e']
            let str = ''
            for (let i = 0; i < 6; i++) {
                // Math.random() * (15 - 0) + 0   表示取0到15之间的值，包括小数
                // Math.round()  表示取整
                let num = Math.round(Math.random() * (15 - 0) + 0)
                // 表示字符串拼接对应索引的数组元素
                str += arr[num]
            }
            console.log(str);
        }

    </script>
</body>

</html>